1 /*
  2  * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #ifndef SHARE_OPTO_MULTNODE_HPP
 26 #define SHARE_OPTO_MULTNODE_HPP
 27 
 28 #include "opto/node.hpp"
 29 
 30 class Matcher;
 31 class ProjNode;
 32 
 33 //------------------------------MultiNode--------------------------------------
 34 // This class defines a MultiNode, a Node which produces many values.  The
 35 // values are wrapped up in a tuple Type, i.e. a TypeTuple.
 36 class MultiNode : public Node {
 37 public:
 38   MultiNode( uint required ) : Node(required) {
 39     init_class_id(Class_Multi);
 40   }
 41   virtual int Opcode() const;
 42   virtual const Type *bottom_type() const = 0;
 43   virtual bool       is_CFG() const { return true; }
 44   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
 45   virtual bool depends_only_on_test() const { return false; }
 46   virtual const RegMask &out_RegMask() const;
 47   virtual Node *match(const ProjNode *proj, const Matcher *m, const RegMask* mask);
 48   virtual uint ideal_reg() const { return NotAMachineReg; }
 49   ProjNode* proj_out(uint which_proj) const; // Get a named projection
 50   ProjNode* proj_out_or_null(uint which_proj) const;
 51   ProjNode* proj_out_or_null(uint which_proj, bool is_io_use) const;
 52 };
 53 
 54 //------------------------------ProjNode---------------------------------------
 55 // This class defines a Projection node.  Projections project a single element
 56 // out of a tuple (or Signature) type.  Only MultiNodes produce TypeTuple
 57 // results.
 58 class ProjNode : public Node {
 59 protected:
 60   virtual uint hash() const;
 61   virtual bool cmp( const Node &n ) const;
 62   virtual uint size_of() const;
 63   void check_con() const;       // Called from constructor.
 64   const Type* proj_type(const Type* t) const;
 65 
 66 public:
 67   ProjNode( Node *src, uint con, bool io_use = false )
 68     : Node( src ), _con(con), _is_io_use(io_use)
 69   {
 70     init_class_id(Class_Proj);
 71     // Optimistic setting. Need additional checks in Node::is_dead_loop_safe().
 72     if (con != TypeFunc::Memory || src->is_Start())
 73       init_flags(Flag_is_dead_loop_safe);
 74     DEBUG_ONLY(check_con());
 75   }
 76   const uint _con;              // The field in the tuple we are projecting
 77   const bool _is_io_use;        // Used to distinguish between the projections
 78                                 // used on the control and io paths from a macro node
 79   virtual int Opcode() const;
 80   virtual bool      is_CFG() const;
 81   virtual bool depends_only_on_test() const { return false; }
 82   virtual const Type *bottom_type() const;
 83   virtual const TypePtr *adr_type() const;
 84   virtual bool pinned() const;
 85   virtual Node* Identity(PhaseGVN* phase);
 86   virtual const Type* Value(PhaseGVN* phase) const;
 87   virtual uint ideal_reg() const;
 88   virtual const RegMask &out_RegMask() const;
 89 
 90 #ifndef PRODUCT
 91   virtual void dump_spec(outputStream *st) const;
 92   virtual void dump_compact_spec(outputStream *st) const;
 93 #endif
 94 
 95   // Return uncommon trap call node if proj is for "proj->[region->..]call_uct"
 96   // null otherwise
 97   CallStaticJavaNode* is_uncommon_trap_proj(Deoptimization::DeoptReason reason = Deoptimization::Reason_none) const;
 98   // Return uncommon trap call node for    "if(test)-> proj -> ...
 99   //                                                 |
100   //                                                 V
101   //                                             other_proj->[region->..]call_uct"
102   // null otherwise
103   CallStaticJavaNode* is_uncommon_trap_if_pattern(Deoptimization::DeoptReason reason = Deoptimization::Reason_none) const;
104 
105   // Return other proj node when this is a If proj node
106   ProjNode* other_if_proj() const;
107 };
108 
109 /* Tuples are used to avoid manual graph surgery. When a node with Proj outputs (such as a call)
110  * must be removed and its ouputs replaced by its input, or some other value, we can make its
111  * ::Ideal return a tuple of what we want for each output: the ::Identity of output Proj will
112  * take care to jump over the Tuple and directly pick up the right input of the Tuple.
113  *
114  * For instance, if a function call is proven to have no side effect and return the constant 0,
115  * we can replace it with the 6-tuple:
116  * (control input, IO input, memory input, frame ptr input, return addr input, Con:0)
117  * all the output projections will pick up the input of the now gone call, except for the result
118  * projection that is replaced by 0.
119  *
120  * Using TupleNode avoid manual graph surgery and leave that to our expert surgeon: IGVN.
121  * Since the user of a Tuple are expected to be Proj, when creating a tuple during idealization,
122  * the output Proj should be enqueued for IGVN immediately after, and the tuple should not survive
123  * after the current IGVN.
124  */
125 class TupleNode : public MultiNode {
126   const TypeTuple* _tf;
127 
128   template <typename... NN>
129   static void make_helper(TupleNode* tn, uint i, Node* node, NN... nn) {
130     tn->set_req(i, node);
131     make_helper(tn, i + 1, nn...);
132   }
133 
134   static void make_helper(TupleNode*, uint) {}
135 
136 public:
137   TupleNode(const TypeTuple* tf) : MultiNode(tf->cnt()), _tf(tf) {}
138 
139   int Opcode() const override;
140   const Type* bottom_type() const override { return _tf; }
141 
142   /* Give as many `Node*` as you want in the `nn` pack:
143    * TupleNode::make(tf, input1)
144    * TupleNode::make(tf, input1, input2, input3, input4)
145    */
146   template <typename... NN>
147   static TupleNode* make(const TypeTuple* tf, NN... nn) {
148     TupleNode* tn = new TupleNode(tf);
149     make_helper(tn, 0, nn...);
150     return tn;
151   }
152 };
153 
154 #endif // SHARE_OPTO_MULTNODE_HPP